Leakproof dry cell



H. R. C.-ANTHONY LEAKPROOF DRY CELL 2 Sheets-Sheet 1 Filed May 31, 1938 Apu-i1 23, 1940.

23, 1940. H. R. c.-ANTHoNY LEAKPROOF DRY CELL 2 Sheets-Sheet 2 Filed lay 31,v 1938 Patented Apr. 23, 1940 Hermann. C. Anthony, Madison, Wis., alalgnor to Bay-O-Vac Company, a corporation of Wisconsin Application my 31, 193s, serial No. 211,07:

8 Claims.

This invention relates to dry-cells of the type used in ash light casings and the like, and more particularly to an improved protective casing for a cell which will prevent fluids from leaking out` of the cell and causing inJury to the casing or other dry-cells within the casing.

In using dry-cells it has been a common experience that if the cell is short circuited, or placed under a heavy load for a considerable length of time, the cell will expand and liquids leak out through the walls of the cell. 'Ihe liquids usually include zinc chloride and ammonium chloride and will, in a short time, injure the metalwalls of the casing which are comll monly ade of brass. If the cell is allowed to remain in the casing for a considerable length of time, it will often swell and freeze to the casing so that it is very dimcult to remove it. Frequently two or more cells are used in a single casing and electrolyte leaking from one cell to another will short circuit the adjacent cell so as to destroy its usefulness and aggravate the damage to the casing. A

Flash light cells usually are manufactured with a wax coated disk in the bottom part of the cell or cup which partially embraces the end of the depolarizing-mix and retards the action of the electrolyte on the bottom wall of the cup. As a result of this protection, the cup usually gives out rst at its side walls, slightly above the bottom, and this-is where the electrolyte is most" likely to leak out after the cell has been in use for a long period. By protecting the side walls of the cup most of the danger of leakage is avoided, but in some cases it is desirable to provide additional protection for the bottom and top of the cell. I n

Another object of the present invention is to provide a strong metal sheath which will closely o and rigidly corinne the een to a giveniengtn and diameter. It has been found that without such protection' cells frequently swell so much in diameter that they stick in the casing and sometimes elongate sumciently to damage the casing.

'I'he zinc commonly used as an electrode and as a y,

cup for the electrolyte is tooy weak by itselfvto prevent such action.

Another object of the invention is to provide a strong metal sheath or jacket which may be insulated from both terminals of the cell so that it will be unnecessary to use an insulating cover or label to prevent the cell from short circuiting on the side walls of the casing.

The invention is illustrated in preferred emu bodiments in the accompany drawings, in which:

(Cl. 13G- 107) Fig. 1 is a vertical sectional view of a lea'rkimmunired dry-cell embodying the invention;

Fig. 2 is a top plan view of the same; Fig. 3 is a bottom plan view; Fig. 4 is a sectional view of the top closure; Fig. 5v is an elevational view showing an insulating wrapper which is preferably provided between the electrode cup and steel jacket; Fig. 6 is a sectional view of an insulating washer, preferably of rubber, which may be applied between the bottom wall of the cell l0 and the inturned flange of the sheath; Fig. 7 is a sectional view of the metal sheath; Fig. 8 is a fragmentary sectional view showing a modied form of .leak-immunized drycell;. Fig /19 is a plan view of the top ofthe cell shown i Fig. 8; Fig. 10 is a bottom plan view of the sa ,i Fig. 11 is a sectional view of another modied form of leakproof cell; Fig. l2 is a sectional view, taken as indicated at line I2 of Fig. 11; and Fig. 13 is a fragmentary elevational view of the zinc elec- 20 trode used in thedevice shown in Fig. 11.

'In the embodiment illustrated in Fiss. 1-7, inclusive,-A designates a zinc cup which serves as a negative electrode for the cell; B, a carbon electrode provided with a depolarizing-mix B'; 2li and-,0, a metal sheath which encloses the cell. The cup A preferably has an annular groove Il in its bottom wall to provide a ilange to be gripped by the lower ange ofthe steel jacket and enable an end portion l5 to be flush with 30 the lower` end of the jacket.v In making up the cell a paper sheet or disk I6 may be placed in the bottom of the cup and bonded to the zinc by heat or pressure to protect the end. A similar protection can be provided by pouring into the can 35 asphalt, wax, or other -free flowing and selfhardening material. Electrolyte I1 is poured into the casing, andthe carbon pole B with its depolarizating-mix B forced down into the cup so that the electrolyte will well-up towards the 40 top of the casing but will allow an air space I8 for gas pressure. Preferably the upper end of the carbon pole B is .provided with a ilanged cap I9 which snuglyilts into an aperture provided in an insulating disk 2li which forms an end closure 45 for the cell. A perforation 2| in the end cap permits venting of gas through the carbon 4terminal.

The sheath- C preferably is made of sheet iron and may be of tubular form with its lower end 50 turned inwardly to form a flange 22. `A rubber sealing washer 23 may 'be placed on the flange 22 before the cell is inserted. In mt cases it is desirable to insulate the casing A from the jacket C, and this may be done by mapping a sheet 2d of insulating material such as rubber, treated paper or the like, around the cell and tucking the lower ends 25 inwardly. ,The cell is then forced into the jacket and pressed iirmly 5 against the washer- 23. The top closure 2l is then forced over the cap I9 and the top edges of the steel jacket are spun inwardly so that the jacket tightly embraces both ends of the cell. Preferably, a spun flange 26 bites into a groove l0 provided in the closure 20 so that a very tight joint is provided.

With a cell of the character above described,

internal pressure formed bygas and expansion` of the electrolyte during use will further tighten the end joints so that no liquid can escape. The i air space I8 permits expansion of the electrolyte and the gas may slowly escape through the perforation 2 I.

If desired, the outer walls of the casing C may be polished and lacquered so as to provide la very attractive appearance and suitable surface for a decalcomana transfer label. In the event that the insulating sheet 2l is omitted, a suitable insulatingcover oi!` cardboard or' the like should be provided.

In the embodiment illustrated in Figs. 8-10, inclusive, an insulating clomre 21 is provided to rest on the inside of an end flange 2l of a steel jacket 29. A rivet-like terminal III is centrally a0 disposed in the closurevmember so as to make contact with the bottom of a zinc cup 3|. Preferably, an insulating sheet 32 separates the steel jacket from the zinc cup. A top closure 3l is also an insulating `disk provided with a terminal 85 34 adapted to contact a carbon electrode 35. After the device has been assembled, an end ilange 36 may be spun into the `disk 33. 'It may be noted in this form that the cell is fully enclosed at both ends and internal pressurewill further tighten the connection.

In the modiiication shown in Figs. 11-13, a zinc cup is not used but the cell is built up within a. tubular steel casing 31 in the following manner. A sleeve of insulating material Il is placed witha in the cylindrical shell 31 and grooves Il and ll are turned in the casing to provide abutments for the end closures. A curled sheet of zinc ll is attached to 'bottom wall I2 by means of a i'lnger` 43 andthe base is then gripped against the abutment formed by the groove 3l byspinning thelower end of the jacket 31 around the edges of the bottom wall 42, as indicated at Il. The bottom wall is protected from the action of the electrolyte by means of an inert disk or sealing wax 45. After electrolyte 4I has been poured into the container, the carbon pole l1 with the usual depolarizing-mix Il is introduced and the insulating closure 49 is fitted over the cap 5l and against the abutment formed by the groove Il. 'I'he upper end of the casing 31 is then spun tightly against the end closure, as indicated at Il, and the cell is ready for use.

As will be readily understood, theA inside of the sheet-metal jacket may be sprayed with suitable insulating material, such as emulsiiied asphalt or the like, instead of using a sheet or collar of insulating material.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, for modifications will be obvious to those skilled in the art. 5

I claim:

1. A leak-immunized nach light drycell provided with circuit terminals at opposite ends, comprising: a hollow cylindrical zinc metal electrode containing electrolytepa centrally disposed 10 carbon electrode and depolarizing-mix in said electrolyte; a bottom closure for the cell afford ing a terminal for one of the electrodes; a top closure for the cell provided with a terminal for the other electrode, electrically insulated from 15 the first mentioned terminal; and a protecting sheet-metal sheath insulated from both of said electrodes and enclosing the side walls of said metal electrode and tightly embracing said closures so as to prevent leakage of the electrolyte 2 from the unit,

2. A device as specied in claim 1, in which the sheet-metalv sheath is insulated from both of the electrodes by an interposed sleeve of paper which has been treated to render it moisture 915 resistant and electrically non-conductive.

3; A device asspeciiled in claim 1,A in which the marginal end portions of the metal sheath are turned inwardly to form flanges which overlap the end closures.

4. In combination: a cell provided with circuit terminals at Vopposite ends; and a liquid tight housing completely enclosing said cell, said housing having a sheet-metal side wall and end walls provided with exposed contact members insulated from each other and insulatedi'rom the sheetmetal side wall. each of said contactsbeing in electrical engagement with one of the cell ter- 5. A unit as specified in claim 4, in which the end walk of the housing comprise disks of strong insulating ilbrous material and the contact members are embedded in said disks.

6. A dry-cell comprising: a tubular shell of ferrous. sheet-metal liavinsr an inner coating of g5 acid resisting material, a metallic base closure fixed to the lower end of said shell and insulated' therefrom; a'metal electrode in said shell electrically connected to the base closure; a centrally disposed carbon electrode and depolarizing 50 mix in the shell; electrolyte partially filling said shell; and a top closure of insulating material nxed to the upper end of the shell to seal the cell against the escape of liquid and having a terminal member insulated from said shell and mgkling electrical contact with said carbon elec- 7. A unit as specied in claim 6, .in which the shell has inwardly directed grooves forming abutments for the end closures, and the end closures 50 are hermetically sealed against said abutments by the ends of the shell clamping thereag'ainst.

8. Anit as specied in claim 6, in. which the metal electrode comprises an open ended curved sheet of zinc'.

' HERMAN R. C. ANTHONY. 

